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Poster: Javik Date: Mar 22, 2005 9:25am
Forum: petabox Subject: Drive spin-down? Low-RPM drives? Power saving?

A question that comes to mind is reducing power consumption and reducing wear-and-tear for the storage drives.

As an outsider I cannot guess at the typical access rate per drive for data in the archive, but I would expect that there are times where most drives aren't doing anything but spin for hours. Do you permit drives to spin down if nothing has been happening for 30 minutes or so?


For a project of this magnitude, I'd think you could get some cooperation from the drive manufacturers to add some features to their drives, such as a two-speed drive that runs at 7200 RPM at full power, and ~2000 RPM in low-power mode.. just fast enough to get the heads to lift off the platters. This way the drive operates at a much-reduced RPM that reduces heat dissipation and extends operational life, yet still allows the drive to be accessible.

For example, spin up to full speed for internal management operations where you don't want to wait all day for the job to finish, then switch to long-life, low-RPM mode for access by the general public.

Lower RPM would directly affect read/write speeds, but how many Internet Archive users can download from the Archive at the sustained 40+ megabytes/sec (about 400 megabit/sec) a 5400 RPM "MaxLine II" Maxtor drive can provide? Drop the RPM to 2700 RPM, and 20+ megabytes/sec is probably still plenty fast for most users connections.


Reference:
http://www.maxtor.com/_files/maxtor/en_us/documentation/data_sheets/maxline_data_sheet.pdf

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Poster: CR Saikley Date: Mar 22, 2005 2:58pm
Forum: petabox Subject: Re: Drive spin-down? Low-RPM drives? Power saving?

Low power modes already exist for the drives we use. For a description, see:

http://www.hitachigst.com/tech/techlib.nsf/techdocs/EBB67181ACB207C586256D340075B4DF/$file/WP_PowerAcoustic_25March.pdf

The performance hit is that you can't read or write until the disk is back to its normal operating state, and the associated recovery time ranges from 0.7-15 seconds depending on the mode used.

The most power-conservative modes entail too long a recovery time to be used across all machines, but could be used on backup drives.

This post was modified by CR Saikley on 2005-03-22 22:58:16

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Poster: HDRJapan Date: Oct 3, 2007 6:14pm
Forum: petabox Subject: Re: Drive spin-down? Low-RPM drives? Power saving?

Is it not true that the more the drive is tagged that the longer the recovery becomes? We have a similar situation with a expired domain search engine at http://www.findeteer.com in which where the drives have a recovery speed unless the drive keeps getting queried.

We have set it so that no matter what the query rate that the system recovers before it accepts the next query in line.

The only drawback is that when the visitor query rate is high the system seems to slow down and even stop at times because of using this methodology. But this solves drive crashes.

We had to do this because a query may look at 10 million domains to shoot out the results.

James
http://www.hdrjapan.com